The disclosure relates to a welding process for the welding of aluminum, in which at least one force sensor measures a force between two welding electrodes on aluminum elements to be welded and transmits its measured values to a welding control. Up to the elapse of a set welding time, the welding control thereby calculates in each case during and/or after the elapse of predeterminable incremental time frames at least one absolute value and/or at least one increase in the measured force and stores it, the welding control comparing the measured absolute value and/or the increase in the measured force in each case with a reference value and/or a reference curve and calculating a control deviation resulting from the comparison.
Welding processes of the generic type are already known for the welding of steel. In such welding processes, the welding control may therefore for example monitor various welding parameters and in particular control a supply of current to the welding electrodes. Such welding processes that are already known cannot however be applied to the special needs of the welding of aluminum. In comparison with steel, aluminum has considerable physical and chemical differences. For example, aluminum differs from steel in the respective melting temperature, which in the case of steel is approximately 1500° C. and in the case of aluminum is approximately 660° C. Consideration must similarly be given to a high-melting oxide film (melting temperature at approximately 2040° C.), which envelops the aluminum parts to be welded together and hinders the welding. In addition, aluminum has a thermal conductivity that is approximately four times higher in comparison with steel. The higher thermal conductivity may have the effect that particularly rapid heat dissipation takes place in particular at the points to be welded, that is to say the welding points, as a result of which structural cracks and/or air inclusions can occur for example at or in the region of the welding points. In other words, such welding processes that are designed for the welding of steel but are used for the welding of aluminum lead to welding points of low quality, and to this extent have for example inadequate strength and/or structural damage.
An object to be achieved is therefore that of providing a welding process for the welding of aluminum that makes it possible for aluminum to be welded particularly easily and inexpensively while avoiding the aforementioned problems.